Zombie rule #X: Human settlements are always a problem. It's only a matter of time before the other shoe drops and the newcomer discover something fucked about them.
But here, the gang failed the basic safety check valid in our world, so even more so when society broke down after an apocalypse. Sure! Let's leave attractive women alone with armed men, what could go wrong? Sure, let's follow some other at the same time we don't know and shouldn't trust in a secluded location!
At least, the new girl in their group should intervene next chapter, but a rape attempt is traumatizing enough so their naivety is already unforgivable to me. And if dude wants to travel around with his personal harem, it's not only fun and games, he should at least be dependable when talking about their safety.